1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 #include <sys/zfs_context.h> 29 #include <sys/dbuf.h> 30 #include <sys/dnode.h> 31 #include <sys/dmu.h> 32 #include <sys/dmu_tx.h> 33 #include <sys/dmu_objset.h> 34 #include <sys/dsl_dataset.h> 35 #include <sys/spa.h> 36 37 static void 38 dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx) 39 { 40 dmu_buf_impl_t *db; 41 int txgoff = tx->tx_txg & TXG_MASK; 42 int nblkptr = dn->dn_phys->dn_nblkptr; 43 int old_toplvl = dn->dn_phys->dn_nlevels - 1; 44 int new_level = dn->dn_next_nlevels[txgoff]; 45 int i; 46 47 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 48 49 /* this dnode can't be paged out because it's dirty */ 50 ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE); 51 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); 52 ASSERT(new_level > 1 && dn->dn_phys->dn_nlevels > 0); 53 54 db = dbuf_hold_level(dn, dn->dn_phys->dn_nlevels, 0, FTAG); 55 ASSERT(db != NULL); 56 57 dn->dn_phys->dn_nlevels = new_level; 58 dprintf("os=%p obj=%llu, increase to %d\n", 59 dn->dn_objset, dn->dn_object, 60 dn->dn_phys->dn_nlevels); 61 62 /* check for existing blkptrs in the dnode */ 63 for (i = 0; i < nblkptr; i++) 64 if (!BP_IS_HOLE(&dn->dn_phys->dn_blkptr[i])) 65 break; 66 if (i != nblkptr) { 67 /* transfer dnode's block pointers to new indirect block */ 68 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED|DB_RF_HAVESTRUCT); 69 ASSERT(db->db.db_data); 70 ASSERT(arc_released(db->db_buf)); 71 ASSERT3U(sizeof (blkptr_t) * nblkptr, <=, db->db.db_size); 72 bcopy(dn->dn_phys->dn_blkptr, db->db.db_data, 73 sizeof (blkptr_t) * nblkptr); 74 arc_buf_freeze(db->db_buf); 75 } 76 77 /* set dbuf's parent pointers to new indirect buf */ 78 for (i = 0; i < nblkptr; i++) { 79 dmu_buf_impl_t *child = dbuf_find(dn, old_toplvl, i); 80 81 if (child == NULL) 82 continue; 83 ASSERT3P(child->db_dnode, ==, dn); 84 if (child->db_parent && child->db_parent != dn->dn_dbuf) { 85 ASSERT(child->db_parent->db_level == db->db_level); 86 ASSERT(child->db_blkptr != 87 &dn->dn_phys->dn_blkptr[child->db_blkid]); 88 mutex_exit(&child->db_mtx); 89 continue; 90 } 91 ASSERT(child->db_parent == NULL || 92 child->db_parent == dn->dn_dbuf); 93 94 child->db_parent = db; 95 dbuf_add_ref(db, child); 96 if (db->db.db_data) 97 child->db_blkptr = (blkptr_t *)db->db.db_data + i; 98 else 99 child->db_blkptr = NULL; 100 dprintf_dbuf_bp(child, child->db_blkptr, 101 "changed db_blkptr to new indirect %s", ""); 102 103 mutex_exit(&child->db_mtx); 104 } 105 106 bzero(dn->dn_phys->dn_blkptr, sizeof (blkptr_t) * nblkptr); 107 108 dbuf_rele(db, FTAG); 109 110 rw_exit(&dn->dn_struct_rwlock); 111 } 112 113 static void 114 free_blocks(dnode_t *dn, blkptr_t *bp, int num, dmu_tx_t *tx) 115 { 116 objset_impl_t *os = dn->dn_objset; 117 uint64_t bytesfreed = 0; 118 int i; 119 120 dprintf("os=%p obj=%llx num=%d\n", os, dn->dn_object, num); 121 122 for (i = 0; i < num; i++, bp++) { 123 if (BP_IS_HOLE(bp)) 124 continue; 125 126 bytesfreed += bp_get_dasize(os->os_spa, bp); 127 ASSERT3U(bytesfreed, <=, DN_USED_BYTES(dn->dn_phys)); 128 dsl_dataset_block_kill(os->os_dsl_dataset, bp, dn->dn_zio, tx); 129 bzero(bp, sizeof (blkptr_t)); 130 } 131 dnode_diduse_space(dn, -bytesfreed); 132 } 133 134 #ifdef ZFS_DEBUG 135 static void 136 free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx) 137 { 138 int off, num; 139 int i, err, epbs; 140 uint64_t txg = tx->tx_txg; 141 142 epbs = db->db_dnode->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 143 off = start - (db->db_blkid * 1<<epbs); 144 num = end - start + 1; 145 146 ASSERT3U(off, >=, 0); 147 ASSERT3U(num, >=, 0); 148 ASSERT3U(db->db_level, >, 0); 149 ASSERT3U(db->db.db_size, ==, 1<<db->db_dnode->dn_phys->dn_indblkshift); 150 ASSERT3U(off+num, <=, db->db.db_size >> SPA_BLKPTRSHIFT); 151 ASSERT(db->db_blkptr != NULL); 152 153 for (i = off; i < off+num; i++) { 154 uint64_t *buf; 155 dmu_buf_impl_t *child; 156 dbuf_dirty_record_t *dr; 157 int j; 158 159 ASSERT(db->db_level == 1); 160 161 rw_enter(&db->db_dnode->dn_struct_rwlock, RW_READER); 162 err = dbuf_hold_impl(db->db_dnode, db->db_level-1, 163 (db->db_blkid << epbs) + i, TRUE, FTAG, &child); 164 rw_exit(&db->db_dnode->dn_struct_rwlock); 165 if (err == ENOENT) 166 continue; 167 ASSERT(err == 0); 168 ASSERT(child->db_level == 0); 169 dr = child->db_last_dirty; 170 while (dr && dr->dr_txg > txg) 171 dr = dr->dr_next; 172 ASSERT(dr == NULL || dr->dr_txg == txg); 173 174 /* data_old better be zeroed */ 175 if (dr) { 176 buf = dr->dt.dl.dr_data->b_data; 177 for (j = 0; j < child->db.db_size >> 3; j++) { 178 if (buf[j] != 0) { 179 panic("freed data not zero: " 180 "child=%p i=%d off=%d num=%d\n", 181 child, i, off, num); 182 } 183 } 184 } 185 186 /* 187 * db_data better be zeroed unless it's dirty in a 188 * future txg. 189 */ 190 mutex_enter(&child->db_mtx); 191 buf = child->db.db_data; 192 if (buf != NULL && child->db_state != DB_FILL && 193 child->db_last_dirty == NULL) { 194 for (j = 0; j < child->db.db_size >> 3; j++) { 195 if (buf[j] != 0) { 196 panic("freed data not zero: " 197 "child=%p i=%d off=%d num=%d\n", 198 child, i, off, num); 199 } 200 } 201 } 202 mutex_exit(&child->db_mtx); 203 204 dbuf_rele(child, FTAG); 205 } 206 } 207 #endif 208 209 static int 210 free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks, int trunc, 211 dmu_tx_t *tx) 212 { 213 dnode_t *dn = db->db_dnode; 214 blkptr_t *bp; 215 dmu_buf_impl_t *subdb; 216 uint64_t start, end, dbstart, dbend, i; 217 int epbs, shift, err; 218 int all = TRUE; 219 220 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); 221 arc_release(db->db_buf, db); 222 bp = (blkptr_t *)db->db.db_data; 223 224 epbs = db->db_dnode->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; 225 shift = (db->db_level - 1) * epbs; 226 dbstart = db->db_blkid << epbs; 227 start = blkid >> shift; 228 if (dbstart < start) { 229 bp += start - dbstart; 230 all = FALSE; 231 } else { 232 start = dbstart; 233 } 234 dbend = ((db->db_blkid + 1) << epbs) - 1; 235 end = (blkid + nblks - 1) >> shift; 236 if (dbend <= end) 237 end = dbend; 238 else if (all) 239 all = trunc; 240 ASSERT3U(start, <=, end); 241 242 if (db->db_level == 1) { 243 FREE_VERIFY(db, start, end, tx); 244 free_blocks(dn, bp, end-start+1, tx); 245 arc_buf_freeze(db->db_buf); 246 ASSERT(all || db->db_last_dirty); 247 return (all); 248 } 249 250 for (i = start; i <= end; i++, bp++) { 251 if (BP_IS_HOLE(bp)) 252 continue; 253 rw_enter(&dn->dn_struct_rwlock, RW_READER); 254 err = dbuf_hold_impl(dn, db->db_level-1, i, TRUE, FTAG, &subdb); 255 ASSERT3U(err, ==, 0); 256 rw_exit(&dn->dn_struct_rwlock); 257 258 if (free_children(subdb, blkid, nblks, trunc, tx)) { 259 ASSERT3P(subdb->db_blkptr, ==, bp); 260 free_blocks(dn, bp, 1, tx); 261 } else { 262 all = FALSE; 263 } 264 dbuf_rele(subdb, FTAG); 265 } 266 arc_buf_freeze(db->db_buf); 267 #ifdef ZFS_DEBUG 268 bp -= (end-start)+1; 269 for (i = start; i <= end; i++, bp++) { 270 if (i == start && blkid != 0) 271 continue; 272 else if (i == end && !trunc) 273 continue; 274 ASSERT3U(bp->blk_birth, ==, 0); 275 } 276 #endif 277 ASSERT(all || db->db_last_dirty); 278 return (all); 279 } 280 281 /* 282 * free_range: Traverse the indicated range of the provided file 283 * and "free" all the blocks contained there. 284 */ 285 static void 286 dnode_sync_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx) 287 { 288 blkptr_t *bp = dn->dn_phys->dn_blkptr; 289 dmu_buf_impl_t *db; 290 int trunc, start, end, shift, i, err; 291 int dnlevel = dn->dn_phys->dn_nlevels; 292 293 if (blkid > dn->dn_phys->dn_maxblkid) 294 return; 295 296 ASSERT(dn->dn_phys->dn_maxblkid < UINT64_MAX); 297 trunc = blkid + nblks > dn->dn_phys->dn_maxblkid; 298 if (trunc) 299 nblks = dn->dn_phys->dn_maxblkid - blkid + 1; 300 301 /* There are no indirect blocks in the object */ 302 if (dnlevel == 1) { 303 if (blkid >= dn->dn_phys->dn_nblkptr) { 304 /* this range was never made persistent */ 305 return; 306 } 307 ASSERT3U(blkid + nblks, <=, dn->dn_phys->dn_nblkptr); 308 free_blocks(dn, bp + blkid, nblks, tx); 309 if (trunc) { 310 uint64_t off = (dn->dn_phys->dn_maxblkid + 1) * 311 (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT); 312 dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0); 313 ASSERT(off < dn->dn_phys->dn_maxblkid || 314 dn->dn_phys->dn_maxblkid == 0 || 315 dnode_next_offset(dn, FALSE, &off, 316 1, 1, 0) != 0); 317 } 318 return; 319 } 320 321 shift = (dnlevel - 1) * (dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT); 322 start = blkid >> shift; 323 ASSERT(start < dn->dn_phys->dn_nblkptr); 324 end = (blkid + nblks - 1) >> shift; 325 bp += start; 326 for (i = start; i <= end; i++, bp++) { 327 if (BP_IS_HOLE(bp)) 328 continue; 329 rw_enter(&dn->dn_struct_rwlock, RW_READER); 330 err = dbuf_hold_impl(dn, dnlevel-1, i, TRUE, FTAG, &db); 331 ASSERT3U(err, ==, 0); 332 rw_exit(&dn->dn_struct_rwlock); 333 334 if (free_children(db, blkid, nblks, trunc, tx)) { 335 ASSERT3P(db->db_blkptr, ==, bp); 336 free_blocks(dn, bp, 1, tx); 337 } 338 dbuf_rele(db, FTAG); 339 } 340 if (trunc) { 341 uint64_t off = (dn->dn_phys->dn_maxblkid + 1) * 342 (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT); 343 dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0); 344 ASSERT(off < dn->dn_phys->dn_maxblkid || 345 dn->dn_phys->dn_maxblkid == 0 || 346 dnode_next_offset(dn, FALSE, &off, 1, 1, 0) != 0); 347 } 348 } 349 350 /* 351 * Try to kick all the dnodes dbufs out of the cache... 352 */ 353 int 354 dnode_evict_dbufs(dnode_t *dn, int try) 355 { 356 int progress; 357 int pass = 0; 358 359 do { 360 dmu_buf_impl_t *db, marker; 361 int evicting = FALSE; 362 363 progress = FALSE; 364 mutex_enter(&dn->dn_dbufs_mtx); 365 list_insert_tail(&dn->dn_dbufs, &marker); 366 db = list_head(&dn->dn_dbufs); 367 for (; db != ▮ db = list_head(&dn->dn_dbufs)) { 368 list_remove(&dn->dn_dbufs, db); 369 list_insert_tail(&dn->dn_dbufs, db); 370 371 mutex_enter(&db->db_mtx); 372 if (db->db_state == DB_EVICTING) { 373 progress = TRUE; 374 evicting = TRUE; 375 mutex_exit(&db->db_mtx); 376 } else if (refcount_is_zero(&db->db_holds)) { 377 progress = TRUE; 378 ASSERT(!arc_released(db->db_buf)); 379 dbuf_clear(db); /* exits db_mtx for us */ 380 } else { 381 mutex_exit(&db->db_mtx); 382 } 383 384 } 385 list_remove(&dn->dn_dbufs, &marker); 386 /* 387 * NB: we need to drop dn_dbufs_mtx between passes so 388 * that any DB_EVICTING dbufs can make progress. 389 * Ideally, we would have some cv we could wait on, but 390 * since we don't, just wait a bit to give the other 391 * thread a chance to run. 392 */ 393 mutex_exit(&dn->dn_dbufs_mtx); 394 if (evicting) 395 delay(1); 396 pass++; 397 ASSERT(pass < 100); /* sanity check */ 398 } while (progress); 399 400 /* 401 * This function works fine even if it can't evict everything. 402 * If were only asked to try to evict everything then 403 * return an error if we can't. Otherwise panic as the caller 404 * expects total eviction. 405 */ 406 if (list_head(&dn->dn_dbufs) != NULL) { 407 if (try) { 408 return (1); 409 } else { 410 panic("dangling dbufs (dn=%p, dbuf=%p)\n", 411 dn, list_head(&dn->dn_dbufs)); 412 } 413 } 414 415 rw_enter(&dn->dn_struct_rwlock, RW_WRITER); 416 if (dn->dn_bonus && refcount_is_zero(&dn->dn_bonus->db_holds)) { 417 mutex_enter(&dn->dn_bonus->db_mtx); 418 dbuf_evict(dn->dn_bonus); 419 dn->dn_bonus = NULL; 420 } 421 rw_exit(&dn->dn_struct_rwlock); 422 return (0); 423 } 424 425 static void 426 dnode_undirty_dbufs(list_t *list) 427 { 428 dbuf_dirty_record_t *dr; 429 430 while (dr = list_head(list)) { 431 dmu_buf_impl_t *db = dr->dr_dbuf; 432 uint64_t txg = dr->dr_txg; 433 434 mutex_enter(&db->db_mtx); 435 /* XXX - use dbuf_undirty()? */ 436 list_remove(list, dr); 437 ASSERT(db->db_last_dirty == dr); 438 db->db_last_dirty = NULL; 439 db->db_dirtycnt -= 1; 440 if (db->db_level == 0) { 441 ASSERT(db->db_blkid == DB_BONUS_BLKID || 442 dr->dt.dl.dr_data == db->db_buf); 443 dbuf_unoverride(dr); 444 mutex_exit(&db->db_mtx); 445 } else { 446 mutex_exit(&db->db_mtx); 447 dnode_undirty_dbufs(&dr->dt.di.dr_children); 448 } 449 kmem_free(dr, sizeof (dbuf_dirty_record_t)); 450 dbuf_rele(db, (void *)(uintptr_t)txg); 451 } 452 } 453 454 static void 455 dnode_sync_free(dnode_t *dn, dmu_tx_t *tx) 456 { 457 int txgoff = tx->tx_txg & TXG_MASK; 458 459 ASSERT(dmu_tx_is_syncing(tx)); 460 461 dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]); 462 (void) dnode_evict_dbufs(dn, 0); 463 ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL); 464 465 /* 466 * XXX - It would be nice to assert this, but we may still 467 * have residual holds from async evictions from the arc... 468 * 469 * zfs_obj_to_path() also depends on this being 470 * commented out. 471 * 472 * ASSERT3U(refcount_count(&dn->dn_holds), ==, 1); 473 */ 474 475 /* Undirty next bits */ 476 dn->dn_next_nlevels[txgoff] = 0; 477 dn->dn_next_indblkshift[txgoff] = 0; 478 dn->dn_next_blksz[txgoff] = 0; 479 480 /* free up all the blocks in the file. */ 481 dnode_sync_free_range(dn, 0, dn->dn_phys->dn_maxblkid+1, tx); 482 ASSERT3U(DN_USED_BYTES(dn->dn_phys), ==, 0); 483 484 /* ASSERT(blkptrs are zero); */ 485 ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE); 486 ASSERT(dn->dn_type != DMU_OT_NONE); 487 488 ASSERT(dn->dn_free_txg > 0); 489 if (dn->dn_allocated_txg != dn->dn_free_txg) 490 dbuf_will_dirty(dn->dn_dbuf, tx); 491 bzero(dn->dn_phys, sizeof (dnode_phys_t)); 492 493 mutex_enter(&dn->dn_mtx); 494 dn->dn_type = DMU_OT_NONE; 495 dn->dn_maxblkid = 0; 496 dn->dn_allocated_txg = 0; 497 mutex_exit(&dn->dn_mtx); 498 499 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); 500 501 dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg); 502 /* 503 * Now that we've released our hold, the dnode may 504 * be evicted, so we musn't access it. 505 */ 506 } 507 508 /* 509 * Write out the dnode's dirty buffers. 510 * 511 * NOTE: The dnode is kept in memory by being dirty. Once the 512 * dirty bit is cleared, it may be evicted. Beware of this! 513 */ 514 void 515 dnode_sync(dnode_t *dn, dmu_tx_t *tx) 516 { 517 free_range_t *rp; 518 dnode_phys_t *dnp = dn->dn_phys; 519 int txgoff = tx->tx_txg & TXG_MASK; 520 list_t *list = &dn->dn_dirty_records[txgoff]; 521 522 ASSERT(dmu_tx_is_syncing(tx)); 523 ASSERT(dnp->dn_type != DMU_OT_NONE || dn->dn_allocated_txg); 524 DNODE_VERIFY(dn); 525 526 ASSERT(dn->dn_dbuf == NULL || arc_released(dn->dn_dbuf->db_buf)); 527 528 mutex_enter(&dn->dn_mtx); 529 if (dn->dn_allocated_txg == tx->tx_txg) { 530 /* The dnode is newly allocated or reallocated */ 531 if (dnp->dn_type == DMU_OT_NONE) { 532 /* this is a first alloc, not a realloc */ 533 /* XXX shouldn't the phys already be zeroed? */ 534 bzero(dnp, DNODE_CORE_SIZE); 535 dnp->dn_nlevels = 1; 536 } 537 538 if (dn->dn_nblkptr > dnp->dn_nblkptr) { 539 /* zero the new blkptrs we are gaining */ 540 bzero(dnp->dn_blkptr + dnp->dn_nblkptr, 541 sizeof (blkptr_t) * 542 (dn->dn_nblkptr - dnp->dn_nblkptr)); 543 } 544 dnp->dn_type = dn->dn_type; 545 dnp->dn_bonustype = dn->dn_bonustype; 546 dnp->dn_bonuslen = dn->dn_bonuslen; 547 dnp->dn_nblkptr = dn->dn_nblkptr; 548 } 549 550 ASSERT(dnp->dn_nlevels > 1 || 551 BP_IS_HOLE(&dnp->dn_blkptr[0]) || 552 BP_GET_LSIZE(&dnp->dn_blkptr[0]) == 553 dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT); 554 555 if (dn->dn_next_blksz[txgoff]) { 556 ASSERT(P2PHASE(dn->dn_next_blksz[txgoff], 557 SPA_MINBLOCKSIZE) == 0); 558 ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[0]) || 559 list_head(list) != NULL || 560 dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT == 561 dnp->dn_datablkszsec); 562 dnp->dn_datablkszsec = 563 dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT; 564 dn->dn_next_blksz[txgoff] = 0; 565 } 566 567 if (dn->dn_next_indblkshift[txgoff]) { 568 ASSERT(dnp->dn_nlevels == 1); 569 dnp->dn_indblkshift = dn->dn_next_indblkshift[txgoff]; 570 dn->dn_next_indblkshift[txgoff] = 0; 571 } 572 573 /* 574 * Just take the live (open-context) values for checksum and compress. 575 * Strictly speaking it's a future leak, but nothing bad happens if we 576 * start using the new checksum or compress algorithm a little early. 577 */ 578 dnp->dn_checksum = dn->dn_checksum; 579 dnp->dn_compress = dn->dn_compress; 580 581 mutex_exit(&dn->dn_mtx); 582 583 /* process all the "freed" ranges in the file */ 584 if (dn->dn_free_txg == 0 || dn->dn_free_txg > tx->tx_txg) { 585 for (rp = avl_last(&dn->dn_ranges[txgoff]); rp != NULL; 586 rp = AVL_PREV(&dn->dn_ranges[txgoff], rp)) 587 dnode_sync_free_range(dn, 588 rp->fr_blkid, rp->fr_nblks, tx); 589 } 590 mutex_enter(&dn->dn_mtx); 591 for (rp = avl_first(&dn->dn_ranges[txgoff]); rp; ) { 592 free_range_t *last = rp; 593 rp = AVL_NEXT(&dn->dn_ranges[txgoff], rp); 594 avl_remove(&dn->dn_ranges[txgoff], last); 595 kmem_free(last, sizeof (free_range_t)); 596 } 597 mutex_exit(&dn->dn_mtx); 598 599 if (dn->dn_free_txg > 0 && dn->dn_free_txg <= tx->tx_txg) { 600 dnode_sync_free(dn, tx); 601 return; 602 } 603 604 if (dn->dn_next_nlevels[txgoff]) { 605 dnode_increase_indirection(dn, tx); 606 dn->dn_next_nlevels[txgoff] = 0; 607 } 608 609 dbuf_sync_list(list, tx); 610 611 if (dn->dn_object != DMU_META_DNODE_OBJECT) { 612 ASSERT3P(list_head(list), ==, NULL); 613 dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg); 614 } 615 616 /* 617 * Although we have dropped our reference to the dnode, it 618 * can't be evicted until its written, and we haven't yet 619 * initiated the IO for the dnode's dbuf. 620 */ 621 } 622